Pharmacokinetics of 5 (and 6)-carboxy-2',7'-dichlorofluorescein and its diacetate promoiety in the liver.

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Zamek-Gliszczynski MJ, Xiong H, Patel NJ, Turncliff RZ, Pollack GM, Brouwer KL

Pharmacokinetics of 5 (and 6)-carboxy-2',7'-dichlorofluorescein and its diacetate promoiety in the liver.

J Pharmacol Exp Ther. 2003 Feb;304(2):801-9.

PubMed ID

12538836 [ View in PubMed

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Abstract

Hepatic disposition of 5 (and 6)-carboxy-2',7'-dichlorofluorescein (CDF) and its diacetate promoiety (CDFDA) was studied in isolated perfused rat livers. Livers from Wistar wild-type and multidrug resistance-associated protein (Mrp)2-deficient (TR(-)) rats were perfused with CDF in the presence or absence of probenecid. Probenecid decreased the recovery of CDF in bile approximately 4-fold in wild-type livers (65 +/- 8% versus 15 +/- 2% of dose over 2 h). In livers from TR(-) rats, CDF was not excreted into bile and probenecid decreased perfusate CDF concentrations in a concentration-dependent manner, in part due to inhibition of Mrp3. Plasma membrane vesicles from rat Mrp2- or Mrp3-transfected Sf9 cells were used to confirm that CDF is a substrate for Mrp2 and Mrp3; probenecid inhibited the transport of CDF by Mrp2 and Mrp3 in a concentration-dependent manner. CDF uptake in collagen sandwich-cultured rat hepatocytes was temperature-dependent and saturable (K(m) = 22 +/- 10 microM; V(max) = 97 +/- 9 pmol/min/mg protein). Uptake of CDF in sandwich-cultured rat hepatocytes was impaired significantly by bromosulfophthalein, a substrate for organic anion-transporting polypeptides (Oatps), but was not modulated by specific Oatp2 or organic anion transporter (Oat) substrates. CDFDA uptake was not saturable, temperature-dependent, or impaired by inhibitors. The hydrolysis of CDFDA to CDF is mediated by basic pH and esterases in biological media. CDFDA passively diffuses into hepatocytes where it is hydrolyzed to CDF. In contrast, CDF appears to be taken up by Oatp-mediated transport into rat hepatocytes and effluxed via Mrp2 into bile and via Mrp3 into sinusoidal blood.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Probenecid	Canalicular multispecific organic anion transporter 1	Protein	Humans	Unknown	Substrate Inhibitor	Details
Probenecid	Canalicular multispecific organic anion transporter 2	Protein	Humans	Unknown	Inhibitor	Details